1. Field of The Invention
The present invention generally relates to the mounting structure of a semiconductor device, and more particularly to a semiconductor device provided with a sheet-like interposer member interposed in the multi-stage bumps stacked and bonded between a mounting chip and a substrate. Further, the present invention relates to a method of manufacturing the semiconductor device.
2. Description of the Related Art
Conventionally, a semiconductor device, such as a ball-grid-array (BGA) package, on which a mounting chip including a semiconductor element is mounted via bump junctions is known widely.
With such semiconductor device, when thermal contraction arises to the bump junctions on the substrate or the mounting chip by the operating environment, they are subjected to the repeated stress over an extended period of time, which is liable to result in the trouble such as a crack or a fracture.
On the other hand, research and development efforts are being made about a semiconductor device applied to an engine control unit mounted on an automotive vehicle, etc.
At the present stage, the specifications of a chassis mount that is provided to mount the engine control unit on the chassis of the vehicle are established, and the verification thereof is advanced.
The above-mentioned semiconductor device requires adequate operational life and high reliability over an extended period of time in order for mounting it in a severe operating environment.
In the near future, the development of an engine control unit that is directly mounted on the engine of an automotive vehicle is due to be started. However, the semiconductor device on the present stage has the problem of the toughness of bump junctions as mentioned above, and it is difficult to attain the operating life and reliability that are demanded for the intended purpose.
For example, Japanese Laid-Open Patent Application No. 2000-22311 discloses a semiconductor device which includes an interposer substrate which connects the solder bumps of the adjoining stages of multi-stage solder bumps stacked and bonded between a printed circuit board and a mounting chip.
The conventional semiconductor device mentioned above is provided in order to prolong the life of the solder bump junctions by absorbing the shearing stress acting on the solder bumps on the upper and lower stages of the multi-stage solder bumps under the normal operating environment (the ambient temperature is, for example, in a range of xe2x88x925 deg. C. to 40 deg. C.) by using the interposer substrate.
However, when the conventional semiconductor device is applied to the severe operating environment (the ambient temperature is, for example, in a range of xe2x88x9240 deg. C. to 125 deg. C.) of the engine control unit, the thermal contraction presented on the printed circuit board or the mounting chip is much greater than that in the normal operating environment.
Therefore, if the conventional semiconductor device is used over an extended period of time in the severe operating environment, the toughness of the interposer substrate that connects the solder bumps of the adjoining stages will become inadequate. In other words, the repeated stress acts on the interposer substrate or the solder bump junctions over an extended period of time, and it is liable to result in the trouble, such as a crack or a fracture, even in the case of the conventional semiconductor device.
Moreover, Japanese Laid-Open Patent Application No. 2000-22311 discloses that a soft film of a porosity material or a ceramic material is used for the interposer substrate, and that the film is formed with a plurality of slit-like openings between the laterally and longitudinally arranged solder bumps in order to absorb the distortion due to the repeated stress.
However, even if such arrangement is used, when it is applied to the severe operating environment of the engine control unit, it is difficult for the conventional semiconductor device to secure the operational life and reliability of the bump junctions over an extended period of time.
An object of the present invention is to provide an improved mounting structure of a semiconductor device in which the above-described problems are eliminated.
Another object of the present invention is to provide a semiconductor device that can secure the operational life and reliability of the bump junctions over an extended period of time even when the semiconductor device is used in a severe operating environment such as the case of being used on an automotive vehicle.
Another object of the present invention is to provide a method of manufacturing a semiconductor device that can secure the operational life and reliability of the bump junctions over an extended period of time even when the semiconductor device is used in a severe operating environment such as the case of being used on an automotive vehicle.
Another object of the present invention is to provide a sheet-like interposer member for use in a semiconductor device that can secure the operational life and reliability of the bump junctions over an extended period of time even when the semiconductor device is used in a severe operating environment such as the case of being used on an automotive vehicle.
The above-mentioned objects of the present invention are achieved by a semiconductor device comprising: a substrate; a mounting chip bonded to the substrate; multi-stage bumps having two or more stages of bumps stacked and bonded so that the substrate and the mounting chip are electrically connected by the multi-stage bumps; and a sheet-like interposer member of a resin material provided in the stacked stages of the multi-stage bumps and having openings each formed between two diagonally arrayed bumps of the multi-stage bumps.
The above-mentioned objects of the present invention are achieved by a semiconductor device comprising: a substrate; a mounting chip bonded to the substrate; multi-stage bumps having two or more stages of bumps stacked and bonded so that the substrate and the mounting chip are electrically connected by the multi-stage bumps; and a sheet-like interposer member of a resin material provided in the stacked stages of the multi-stage bumps and having openings each formed between two diagonally arrayed bumps of the multi-stage bumps, the interposer member having joint portions each interconnecting two adjacent bumps of the multi-stage bumps.
The above-mentioned objects of the present invention are achieved by a sheet-like interposer member for use in a semiconductor device including a substrate, a mounting chip bonded to the substrate, and multi-stage bumps having two or more stages of bumps stacked and bonded so that the substrate and the mounting chip are electrically connected by the multi-stage bumps, the interposer member provided in the stacked stages of the multi-stage bumps and having openings each formed between two diagonally arrayed bumps of the multi-stage bumps.
The above-mentioned objects of the present invention are achieved by a semiconductor device comprising: a ball-grid-array package; multi-stage bumps having two or more stages of bumps stacked and bonded so that the ball-grid-array package and an external integrated-circuit board are electrically connected by the multi-stage bumps; and a sheet-like interposer member of a resin material provided in the stacked stages of the multi-stage bumps and having openings each formed between two diagonally arrayed bumps of the multi-stage bumps.
The above-mentioned objects of the present invention are achieved by a method of manufacturing a semiconductor device including a substrate, a mounting chip bonded to the substrate, multi-stage bumps having two or more stages of bumps stacked and bonded so that the substrate and the mounting chip are electrically connected by the multi-stage bumps, and a sheet-like interposer member of a resin material provided in the stacked stages of the multi-stage bumps and having openings each formed between two diagonally arrayed bumps of the multi-stage bumps, the method comprising the steps of: bonding first bumps to a first surface of the interposer member; bonding second bumps to the mounting chip; bonding the first bumps of the first surface of the interposer member and the second bumps of the mounting chip by using a first bonding material applied to a second surface of the interposer member opposite to the first surface, so that the multi-stage bumps are formed with the interposer member and the mounting chip bonded together; applying a second bonding material to the substrate; and bonding the multi-stage bumps with the interposer member and the mounting chip bonded together, to the substrate by using the second bonding material applied to the substrate.
The above-mentioned objects of the present invention are achieved by a method of manufacturing a semiconductor device including a substrate, a including a substrate, a mounting chip bonded to the substrate, multi-stage bumps having two or more stages of bumps stacked and bonded so that the substrate and the mounting chip are electrically connected by the multi-stage bumps, and a sheet-like interposer member of a resin material provided in the stacked stages of the multi-stage bumps and having openings each formed between two diagonally arrayed bumps of the multi-stage bumps, the method comprising the steps of: bonding first bumps to a first surface of the interposer member; bonding the first bumps of the first surface of the interposer member to the substrate by using a first bonding material applied to the first surface; applying a second bonding material to a second surface of the interposer member opposite to the first surface; bonding second bumps to the mounting chip; and bonding the second bumps of the mounting chip and the first bumps of the interposer member with the substrate bonded thereto by using the second bonding material applied to the second surface, so that the multi-stage bumps are formed with the interposer member and the mounting chip bonded together. In the mounting structure of the semiconductor device of the present invention, the novel and useful sheet-like interposer member which is different from the conventional interposer member is used. When the semiconductor device is used in the severe operating environment of an engine control unit mounted on an automotive vehicle, the repeated stress acting on the bump junctions can be eased as much as possible, and the operating life and reliability can be improved by using the sheet-like interposer member.
Moreover, according to the manufacturing method of the semiconductor device of the present invention, the semiconductor device with high reliability can be produced with low cost by carrying out the known manufacturing processes with the sheet-like interposer member.